Red Flag Warning 2, NWS Guam

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
807 AM CHST MON APR 18 2016

.SYNOPSIS...
PGUA DOPPLER WEATHER RADAR SHOWS ISOLATED TRADE-WIND SHOWERS
MOVING THROUGH THE MARIANAS WATERS. THE VAD WIND PROFILE REVEALS
EAST WINDS OF 12 TO 22 KNOTS THROUGH THE LOWEST 8 THOUSAND FEET OF
THE AIR.

&&

.DISCUSSION...
VERY DRY PATTERN OVER THE LAST 9 DAYS LOOKS SET TO CONTINUE FOR A
WHILE. THE DROUGHT PHASE OF THIS EL NINO EVENT IS DOMINATING THE
WEATHER ALL OVER MICRONESIA...INCLUDING THE MARIANAS. BOTH THE
GFS40 AND THE ECMWF-HIRES PROG THE DRYNESS TO CONTINUE THROUGH THE
FORECAST PERIOD WITH A HALF INCH OF RAIN OR LESS THROUGH THE NEXT
10 DAYS. MARCH RAIN FALL WAS ONLY 60 PERCENT OF NORMAL AND SO FAR
APRIL IS ONLY 25 PERCENT OF NORMAL. FEBRUARY WAS 80 PERCENT OF
NORMAL...BUT JANUARY WAS ONLY 53 PERCENT OF NORMAL. DECEMBER 2015
WAS 63 PERCENT OF NORMAL. NOVEMBER 2015 WAS 65 PERCENT OF NORMAL.
SO THAT IS 6 MONTHS OF BELOW NORMAL RAINFALL AND THE PAIN IS NOT
OVER YET. THE KEETCH-BYRAM DROUGHT INDEX IS NOW 756 AND IS
EXPECTED TO PASS 760 WEDNESDAY. IT COULD THEN PASS 770 NEXT
THURSDAY THE 28TH OF APRIL IF THE DRY WEATHER CONTINUES. THESE ARE
THE HIGHEST KBDI VALUES SINCE 2010. COMBINED WITH LOW AFTERNOON RH
AND WINDS THAT ARE A LITTLE ABOVE NORMAL WILL LIKELY CREATE
CRITICAL FIRE WEATHER CONDITIONS TODAY AND PERHAPS TUESDAY ALSO.

&&

.EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS CLOUD COVER INCREASING EAST OF THE MARSHALL
ISLANDS IN ADVANCE OF A TRADE-WIND DISTURBANCE NEAR THE DATE LINE.
MODELS ARE IN GOOD AGREEMENT IN DEVELOPING A TRADE-WIND CONVERGENCE
ZONE AND BAND OF RAINFALL FROM KOROR TO THE MARSHALL ISLANDS OVER
THE NEXT FEW DAYS. HOWEVER...LATEST MODEL RUNS SHOW THE HEAVIEST
PRECIP REMAINING SOUTH OF MAJURO...OR GENERALLY SOUTH OF 7N. GFS
SHOWS SIGNIFICANT ACCUMULATIONS AT POHNPEI LATER THIS WEEK BUT RUN-
TO-RUN CONSISTENCY HAS BEEN LACKING SO LEFT ISOLATED COVERAGE FOR
NOW THROUGH THE WEEK UNTIL A FEW MORE MODEL RUNS CAN BE ASSESSED.
INCREASED SHOWER COVERAGE AT KOSRAE TO SCATTERED TUESDAY NIGHT AND
WEDNESDAY AS KOSRAE IS SITUATED FARTHER SOUTH WHERE THE HEAVIEST
CONVECTIVE BAND IS PROGGED TO DEVELOP. MANY LOCATIONS SOUTH OF 7N
COULD SEE SIGNIFICANT WETTING RAINS. HOWEVER...RAINFALL DISTRIBUTION
COULD STILL BE SPOTTY BUT BENEFICIAL NONETHELESS.

WINDS AND SEAS CONTINUE TO INCREASE ACROSS THE MARSHALL ISLANDS.
SATELLITE ALTIMETRY AND SCATTEROMETER DATA INDICATE COMBINED SEAS
AND WINDS ARE HAZARDOUS TO OPERATORS OF SMALL CRAFT. WINDS WILL
SUBSIDE BELOW HAZARDOUS LEVELS TUESDAY BUT SEAS WILL REMAIN ELEVATED
THROUGH MIDWEEK AT MAJURO. IN ADDITION...TRADE-WIND WAVES AND SWELL
CONTINUE TO SUPPORT HAZARDOUS SURF ALONG EAST FACING SHORES OF
KOSRAE AT LEAST THROUGH THE NEXT COUPLE OF DAYS. WAVE WATCH GUIDANCE
SHOWS SEAS DIMINISHING EARLY WEDNESDAY WITH SURF EXPECTED TO FALL
BELOW ADVISORY LEVELS LATE WEDNESDAY.

&&

.WESTERN MICRONESIA...
DRY CONDITIONS PREVAIL ACROSS THE REPUBLIC OF PALAU AND YAP AND
CHUUK STATES WITH LARGE SCALE SUBSIDENCE EVIDENT IN SATELLITE
IMAGERY AND SOUNDING DATA ACROSS THE ENTIRE REGION. A WEAK TRADE-
WIND CONVERGENCE IS EXPECTED TO BRING MORE CLOUD COVER TO YAP
TONIGHT AND TUESDAY BUT SHOWERS WILL BE LIGHT AND ISOLATED IN
COVERAGE. A MORE ACTIVE WEATHER PATTERN WILL EMERGE BEGINNING LATE
TUESDAY ACROSS MICRONESIA PROVIDING THE OPPORTUNITY FOR MUCH NEEDED
RAINFALL AT KOROR...YAP AND CHUUK FOR THE LATTER HALF OF THE WEEK.

VERY DRY CONDITIONS WILL CONTINUE THROUGH MONDAY FOR KOROR...YAP AND
CHUUK. A TRADE-WIND CONVERGENCE PATTERN WILL DEVELOP TUESDAY AND
WEDNESDAY BRINGING INCREASED CLOUD COVER AND SHOWERS WHICH COULD
HELP ALLEVIATE DROUGHT EFFECTS AT LEAST IN THE SHORT TERM.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...FIRE WEATHER WATCH THROUGH WEDNESDAY AFTERNOON FOR GUZ001.

MARIANAS WATERS...NONE.
&&

STANKO/WILLIAMS